An engine combusts a mixture of air and fuel within cylinders to drive pistons that rotatably turn a crankshaft to generate drive torque. Exhaust gas resulting from combustion is expelled from the cylinders into an exhaust system. The exhaust system includes exhaust treatment components to decrease emissions. One example exhaust treatment component for engines is a selective catalytic reduction (SCR) system. SCR systems inject a reductant, e.g., urea solution, into the exhaust system upstream from an SCR catalyst. The mixture of the reductant and the exhaust gas reacts with the SCR catalyst, thereby decreasing emissions, such as nitrogen oxides (NOx). At freezing or below-freezing temperatures, the reductant in the reductant injector and/or the reductant tank freezes, thereby inhibiting the injection of the reductant. Thermal shields, heaters, and/or temperature sensors for the reductant injector are conventionally implemented to assist in thawing or preventing freezing of the reductant injector, but these components increase costs. Thus, while these systems work for their intended purpose, there remains a need for improvement in the relevant art.